Protective means for insulation



y 20, 1965 P. F. KOEHLY ETAL 3,

PROTECTIVE MEANS FOR INSULATION Original Filed Jan. 23, 1961 2Sheets-Sheet l INVENTORS Paul F? Koehl BY E0!" WQII'QFS, Jr.

Their- A fforney July 20, 1965 P. F. KOEHLY ETAL PROTECTIVE MEANS FORINSULATION 2 Sheets-Sheet 2 Original Filed Jan. 23. 1961 INVENTORS PaulF. Koeh/y BY Earl C. WaI'ferqJr.

Fig. 6

Their Affdrnev United States Patent 3,196,304 PRQTE CTEVE MEANS FORlNSiJLA'il-IQN Paul F. Koehiy and Earl C. Waiters, in, Dayton, Ohio,assignors to General Meters Corporatien, Detroit, Mich, a corporation ofDelaware riginal application .Fan. 23, 1961, No. 84,139, new Patent No.3,ti97,329, dated July 9, 1963. Divided and this application Nov. 6,1962, Ser. Ne. 235,786) 1 Claim. (Cl. 310-194) This invention relates tomeasures for protection of insulation on metal components andparticularly, to avoidance of breakdown and failure of insulatingmaterial along edges of tooth-like radial projections of metal whichdefine slots to be fitted with conductive windings for retentiontherein.

This is a division of parent application SN. 84,189- Koehly, et al.,'filed January 23, 1961, now Patent 3,097,320-Koehly et al., issued July9, 1963, and belonging to the assignee of the present invention.

An object of this invention is to provide new and improved laterallyprojecting means on teeth of insulationcovered magnetic cores to beprotected against breakdown and failure detrimental to performance andsatisfaction in quality as well as reliability of a product providedtherewith.

Another object of this invention is to provide a toothed laminationassembly having embossed projections to eliminate sharp edges alongwhich an insulating covering can fail and to have a substantiallyU-shaped cross-section with an outer surface coverable with materialsuch as epoxy and the like.

Another object of this invention is to provide a toothed laminationassembly having laterally projecting means cast of material such asaluminum and the like to form an integral hub pontion as well as curvedportion between the hub and projecting means so as to permitsubstantially uniform coating thereof with insulating material such asepoxy and the like. 1

A further object of this invention is to provide a method and means ofhaving a cast hub with radial ribs in alignment with each of a pluralityof teeth between Winding slots and adaptable to include an outer endhook to avoid winding slip-off on a dynamoelectric machine componentsuch as a stator provided with fluidized-bed applied insulation materialsuch as epoxy that substantially uniformly covers at least the radialribs and teeth.

Another object of this invention is to provide a toothed laminationassembly having laterally projecting rib means cast in alignment with aplurality of teeth to define windring slots and extending radially forsubstantially rounding corners about which windings can be fittedrelatively free of sharp edges where insulation failure would previouslyoccur and simultaneously providing smooth and gradual surfaces ontowhich uniform coating of insulation can be added subsequent totie-greasing thereof after casting.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein preferred embodiments of the present invention areclearly shown.

In the drawings:

FIGURE 1 is an end View of a dynamoelectric machine having one componentwith slot-forming teeth having laterally projecting means embossed in anend lamination in accordance with the present invention.

FIGURE 2A represents one embodiment in a fragmentary cross-sectionalview taken along line A--A in FIG- URE 1.

FIGURE 3A represents another embodiment in another fragmentarycross-sectional view also taken along line A-A in FIGURE 1.

FIGURE 4 is an end view of die means for use in casting laterallyprojecting ribs in alignment with slot-forming teeth in accordance withthe present invention.

FIGURE-5 is a cross-sectional view of the die means taken along line 55in FIGURE 4.

FEGURE 6 represents casting of molten metal such as aluminum into diemeans assembled for integrally forming a lamination hub portion andlaterally projecting rib means in accordance with the present invention.

FIGURE 7 is an end view of a dynamoelec-tric machine component having ahub portion and rib means cast therein and divided diagonally toillustrate differing embodimerits.

FIGURE 7X is a cross-sectional view taken along line XX in FIGURE 7.

FIGURE 8 is a cross-sectional view taken along line 8-3 in FIGURE 7.

FIGURE 9 is a cross-sectional View taken along line 99 in FIGURE 7.

Use of slotted laminated components covering with a substantiallyuniform coating of plastic particles made of material such as nylon,polyethylene, epoxy resin, arcylics, vinyls and the like suspended in asolid state in a gaseous medium is disclosed in co-pending applicationsS.N. 64,324 filed October 24, 1960, now abandoned, as Well as S.N.737,590 filed May 26, 1958, now abandoned, and both belonging to theassignee of the present inven- .tion. Previously it was customary to fitindividual slot liners into space between teeth of laminated assembliesused to form a dynamoelectric machine stator or rotor component. Theseseparable slot liners can add to cost and time required for manufactureof a slotted lamination assembly or component. However, use of theseparate slot liners would generally avoid electrical shorting due todamage of insulation as conductors or wiring were fitted tightly intothe slots of a particular dynamoelec tric machine component. Generally,such a lamination assembly is formed by forming a stack of slottedpieces generally aligned relative to each other and suitably heldtogether such as by welding, rivets, through bolts and other fasteningmeans also to be used in accordance with the present invention. However,as an improvement the present invention relates to modification ofstructure adjacent to or integrally with a pair of opposite endlaminations so as to avoid sharp edges which can contribute to failureand breakdown of electrical insulation including insulating covering-sof wiring as well as inclulating plastic material that is substantiallyuniformly coated over metal edges and surfaces of a slotted laminationassembly or component. Features of the present invention can beincorporated on dynamoelectric machines having inside-out stator androtor arrangements as disclosed for a ventilating means of copendingapplication S.N. 816,560Levy et al., filed May 28, 1959, now Patent990,112 issued June 27, 1961, as well as to dynamoelectric machinesarranged more conventionally to have a stator component locatedconcentrically and radially outside a rotor component journalledcentrally thereof.

For purposes of illustration, features of the present invention areshown on an inside-out type stator and rotor arrangement with referenceto FIGURE 1 wherein a laminated rotor assembly or component 10 isprovided with east end ring means 11 which form part of a socalledsquirrel-cage winding including conductor bars that pass through alignedslots of the rotor 10 in a Wellknown manner. Suitable ventilating bladesand fan means can be mounted or formed integrally on this rotor 10 inaccordance with the copending application S.N. 816,560, new Patent2,990,112, identified earlier. Located radially inside this rotor 10there is a stator subassembly or component generally indicated bynumeral 12 and including a plurality of sheet metal laminations L eachhaving radially located slots S substantially longitudinally alignedwith each other and adapted to be fitted with conductive wiring orwindings W having a suitable insulating covering thereon. Each of thesheet metal laminations L as well as end lamination 14 includes aplurality of teeth T radially displaced a predetermined angular distancefrom each other and defining the slots S. The stator component 12includes a pair of opposite end laminations 14 also having slots asdefined by teeth complementary to slots and teeth of laminations L.However, each of the teeth of each end lamination 14 differs from teethof the laminations L in that there is provided a laterally outwardlyprojecting and radially extending embossed portion 15 substantiallylongitudinally in alignment with each of the teeth such as T in onlyeach of the end laminations on opposite sides of the stack oflaminations L. A plastic coating of insulating material 16 provides asubstantially uniform covering that extends over and around thisembossed portion 15 as well as edges of the sheet metal laminations Land surfaces thereof. FIGURE 2A shows a fragmentary cross-sectional viewof one of these teeth of the end lamination 14 and more particularly anembossed portion 15 having a V-shape below which there is an open space17. FIG- URE 3A illustrates a slightly modified structure in which thereis a U-shaped cross-sectional embossed portion 15-U around whichconductor wiring W can be looped without encountering any sharp edges orbends since the V-shaped or U-shaped embossed portions provide asubstantially rounded backing covered with an insulating coating 16. TheU-shaped embossed portion shown in FIGURE SA has an open space 18thereunder. Thus the coating 16 of insulating material such as epoxy hasa substantially rigid backing for rounding of corners adjacent to endlamination teeth. The laminations L as well as end laminations 14 can bemounted on a suitable sleeve or hub member 19 in a manner similar tothat disclosed in copending application S.N. 816,560, now Patent2,990,112, identified earlier.

In some instances it has been found that provision of a coating ofinsulating material, such as 16, when applied to end laminationsprovided with embossed portions and open spaces such as 17 and 18, therecan be objectionable pin-size holes along an underside of the endlamination edges or teeth. A possibility exists that this minorimperfection results from presence of the open spaces 17 and 18 belowthe embossing in which a temperature differential can arise due toheating of the lamination assembly for application of the insulatingcoating 16 as disclosed in application S.N. 64,324 identified earlier.Apparently, some heated air can be trapped in the open spaces 17 and 18and covering of the surfaces and edges with a sufiiciently thick layerof insulating material 16 can generally overcome presence of suchpinsize holes through which such breathing can occur. However, by use ofa procedure involving die parts for casting of molten metal such asaluminum into a hub structure for the laminations such as L it ispossible to provide structural features in accordance with the presentinvention and further avoid any irregularities including thinning of theinsulation coating 16 in corners and along edges. FIGURE 4 illustrates aplan view of a die means 20 having a central recess 21 connectedwithaxial sprue passages 22. This die means 20 is shown also in views ofFIGURES and 6. The die means 26 has a plurality of radially outwardlyextending recesses 23 into which molten metal can be cast integrallywith metal used to form a hub portion around a central support member orshaft 24 that can have an enlarged mid-portion 25 and an end 26 adaptedto complement a central aperture 27 of the die part 20. Four or moredowels 28 can be used to hold die means 20 in a predetermined locationwith respect to a secondary die means 29 that 41. can be fitted with acentrally apertured cover plate 34) having a passage 31 therein throughwhich molten metal can be cast into the die means. It is to be notedthat radially extending recesses 23 are to be provided in both the diemeans 20 and 29 so as to form raised portions or ribs to extendlaterally outwardly and longitudinally in alignment with teeth such as Tof a stator component 32 illustrated in FIGURE 7 and adapted to fitbetween the die parts or means 20 and 29 as indicated in FIGURE 6. Acast metal annular hub portion 33 is formed by use of these die means 20and 29 which simultaneously can form cast ribs or laterally outwardlyextending projecting means 34 in alignment with each of the teeth T andextending longitudinally thereof. The radially'lnner ends of these ribs34 are integral with the cast hub portion 33. It has been found that thecast metal such as aluminum used in the hub portion as well as the ribmeans 34 sticks to sides of the flat end laminations which aresubsequently covered with an insulation coating 36 shown .in FIGURES 7X,8 and 9. This covering of insulating material is provided in accordancewith the copending applications identified earlier and covers not onlythe hub portion 33 but also the rib means 34 as indicated in certainviews of the drawings. The rib means 34 can have any suitablecross-section and preferably have a substantially U-shaped exteriorsurface over which the insulation covering 36 is added. Thus the wiringor winding W has a rounded backing adjacent to the end laminationsbecause of the provision of the rib means 34 extending laterallyoutwardly as well as longitudinally in alignment with each of the teethsuch as T. It is to be noted that suitable de-greasing of the cast metaland laminations should occur prior to adding of an insulating coveringin a substantially uniform layer over surfaces of the stator assemblysuch as 32.

It is to be understood that junctures of the rib means 34 at a radiallyinner location thereof integral with the hub portion 33 results incorners which are hard to fill and cover with an insulating coating suchas 36 and therefore intermediate shoulder means such as 37 and 38 can becast between the rib means 34 and hub portions 33 on opposite sides withrespect to flat end laminations. The shoulders 37 are substantiallyconvex in cross-section as indicated by FIGURE 8 whereas the shoulders38 are concave in cross-section as shown in FIGURE 9. In view ofpresence of limited sharpness of corners between the shoulders 37 andhub portion 33 as well as end lamination L and rib means 34 there isstill some possibility for slight irregularity in covering and fillingwith the insulating material 36 in the configuration shown by FIGURE 8.Thus the preferred structure is that shown in FIGURE 9 whereinsubstantially all junctures of the shoulders 38 with the hub portion 33and rib means 34 on each end lamination are relatively smooth andgradual and adapted for uniform coating with plastic particles ofinsulating material as noted earlier.

In a lower portion of the structure illustrated by FIG- URE 7 as well asin the cross-sectional view of FIGURE 9 there is also shown an outerhook end or projection 39 integral with and extending laterally from ribmeans 34. This hook end 39 results in an outward extension 40 of theinsulation coating such as 36 and provides an abut ment or stop forwiring or winding means W fitted around teeth defining slots S. Thewiring or winding means W can be kept from'slipping off of the teeth byprovision of this stop portion 39-40 provided adjacent to an end of eachof the cast rib means along each tooth. It is to be understood thatembossings such as illustrated in FIG- URES 2A and 3A can also beprovided with such outwardly extending stop portions. Thus theembossings as well as the rib means together with the teeth of thedynamoelectric machine components become encapsulated in an insulatingcoating rounded off adjacent to end lamination teeth. A substantiallyuniform thickness of insulating material in the form of coatings 16 and36 can be applied to the metal of the dynamoelectric machine components12 and 32 and shoulders such as 37 and 38 avoid thinning andirregularity of such coating material. In most instances the embodimentof FIGURE 8 without the stop members 39-40 and with the convex-shoulders37 provides adequate protection for wiring or winding means W fittedinto slots S around teeth T. Use of the cast metal for integralformation of hub portion 33 as well as rib means 34 avoids formation ofpin-size holes due to pres ence of any voids or open spaces since therib means 34 are cast of solid metal. In any event, previously providedflat surfaces of end laminations are changed to outwardly projected endlaminations having rib means or embossed portions radially in alignmentwith teeth such as T. For a twenty-four-slot stator component theseteeth and also the embossed portions or rib means are substantially 15apart mechanically.

It is to be noted that a possibility exists for utilizing theembodiments of FIGURES 8 and 9 both having cast rib means 34 as well asa cast hub portion 33 to further include a groove or slot as well as apassage drilled through a particular longitudinally aligned stack ofteeth and casting molten metal into this groove or slot or passage so asto form one closed loop in at least one of the stack-ups of teethbetween a pair of slots S. The loop can form a shading ring fordisplacement of electrical flux in this one stack-up of teeth and thusit is possible for a shaded-pole inside-out motor to be formed inaddition to having the embossed portions and rib means as describedearlier.

It is to be noted that the insulation coatings such as 16 and 36 appliedover the edges and surfaces including the embossed portions and ribmeans can further enhance the holding together of the laminations aswell as any cast metal parts added thereto. Thus the insulation coating36 applied as shown in FIGURES 8 and 9 can aid in assuring maintenanceof rib means 34 in lateral and longitudinally extending relationship tothe teeth of opposite end laminations. Also it is to be noted that thewiring or winding means W once fitted into the slots S and around therounded bends as backed by the embossed portions and rib means which areinsulation covered will assure maintenance of positioning of theseembossed portions and rib means in predetermined aligned relationshipwith respect to a particular stack-up of teeth. Insulation of the wiringor winding means W as well as the insulation coatings 16 and 36 areprotected by provision of the rounded backing as provided by theembossed portions 15 as well as the rib means 34 that extend laterallyoutwardly and longitudinally with respect to the teeth radially integralwith a stator lamination assembly or component. It is to be understoodthat embossed portions 15 as well as rib means 34 cast into positionadjacent to end laminations can be used on a stator component as well asrotor means to be provided with wiring or windings W on either insideoutmotors and generators as well as dynamoelectric machines having statorsprovided radially outside rotors.

While the embodiments of the present invention as herein disclosedconstitute preferred forms, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

In a toothed lamination assembly including a stack of metal laminationseach with radial teeth aligned axially of each other to form slotsfitted with conductive windings which engage an insulation coating ofepoxy resin material along the slots and around opposite end laminationseach primarily embossed to project axially away from the slot-forminglaminations only in alignment with the radial teeth, the improvementwhich comprises a secondarily embossed end abutment integral with theopposite end laminations for each of the teeth where primarily embossedto project axially away from the slot-forming laminations, each saidsecondarily embossed end abutment extending only axially for apredetermined distance as a stop for retention of windings in the slotsas fitted therein against slipping off of the teeth radially outwardlythereof, each said secondarily embossed end abutment having theinsulation coating of epoxy resin material encapsulated peripherallythereon including axially and radially thereof everywhere except in adirection toward the lamination teeth forming the slots and having anaxially rounded off configuration spaced radially inwardly of outerperipheral endings of teeth as well as definitely less in width thanindividual tooth width so that each said secondarily embossed endabutment stops winding slip-off specifically in a location axiallyadjacent to the end laminations at a radially inward junction whereprimarily embossed for a width also less than individual tooth width sothat the insulation coating of epoxy resin material is contouredintegrally and uniformly to complement the opposite end laminations bothwhere primarily embossed only radially of the teeth and wheresecondarily embossed at each said integral end abutment always for awidth less than that of radially outer endings of the teeth.

References Cited by the Examiner FOREIGN PATENTS 360,347 6/38 Italy.950,481 10/56 Germany.

MILTON O. HIRSHFIELD, Primary Examiner.

